Common-battery lock-out telephone system.



H..J. ROBERTS. COMMON BATTERY LOOK-OUT TELEPHONE SYSTEM.

. V AP ELIOATION FILED OUT. 22, 1 90B. 996,143, Patented June 27, 1911.

2 SHEETS-SHEET 1.

H. J. ROBERTS.

COMMON BATTERY LOOK-OUT TELEPHCNE SYSTEM.

APPLICATION IILBD 001x22, 19oz}.

, Patented June 27, 1911.

J. ROBERTS, OF EVANSTON, ILLINOIS, ASSIGNOR, TO HOMER ROBERTS TELE- IHONE 00., OF CHICAGO, ILLINOIS, A CORPORATION OF WEST VIRGINIA.

COMMON-BATTERY LOCK-OUT TELEPHONE SYSTEM.

Specification of Letters Patent. Patented June 27 1911,

Application. filed October 22, 1908. Serial No. 458,928.

of Illinois, have invented certain new and useful. Improvements in Connnon-Battery Lock-Out Telephone Systems, of wlnch the fi )llowing is a specification.

. This invention relates to improvements in common battery lock-out telephone systems. Among the salient objects of the invention are to provide a practical system of the character stated; to provide in a system of the general character described, improved substation circuit connections and associated mechanism whereby proper talking connections are attained at any given selected station and the inductive effects of other stations practically eliminated, thus giving an efficient talking circuit; to provide a. system -in wh ch continuous connections are provided at all times for signaling purposes, yet thecircuits-so organized as to prevent substantial nterference with conversations by calling-in parties; to provide a common battery system in which the selection is eifected by successively extending a metallic loop circuit from central to and through the successivest-ations, and practically eliminating the resistance at each station as it is successijvely passed, thus affording a most efficient and non-marginal circuit for operating the selecting mechanisms; to provide a system in which the arrival at the end of the party-line by the successive selection of statlons'thereon results in automatically bringing into operation mechanism which restores thecntire line to normal; to provide in a common battery system means whereby any subscriberfon such line may by the simple of signaling-in place his station in set condition, whereby it will beautomatically selected by the mechanism controlled at central and without necessarily involving the knowledge on the part of the exchange operator as to what station is so selected; to provide in a lock-out system means whereby the automatic selection of a station-as last above described is accompanied by the automaticestablishment of talking connect-ions and the giving of an audible signal to the subscriber; to provide in a common battery lockout system means whereby two or more par- .ties upon the same party-line may be given talking connections to the exclusion of all other stations; to provide in such a system a supervisory signaling system which does not clash or interfere with any of the operations of calling-in or selecting; to provide a system of the character referred to which is characterized by affording absolute supervision by the central operator and precludes interfering on the part of the subscriber; and in general to provide a simple, practical and etficient system of. the character referred to. The most of the apparatus employed in this system is of conventional construction, or so nearly that as to be readily understood by those skilled in the art and therefore to require no special description other than its connections in the system. The two main instruments at each sub-station are, however, special relays, which will be described before describing the circuit connections.

Referring to the drawingsFigure 1 is a diagrannnatic view of an external circuit and so much of the exchange as is necessary strument which will be herein termed the,

lock-out relay; the function of this latter instrument being to control certain circuit connections in addition to operating as a. ringer. The magnet of the relay S has two differently wound spools, 1 and 2, the former being included in both main limbs of the telephone line and wound so that current flowing outon one limb and back 'on the other neutralizes or produces no inductive cifcct in the spool. The spool 2 has a'single ordinary winding. Upon the yoke 12-of the magnet is mounted a group of three springs -a switch-spring 4t, a back contact spring a and a forward contact spring 6. The armature 7, pivoted upon the yoke as usual, carries an arm having an insulated button 8 adapted to engage and depress the springs 4 and 5 into engagement with the front spring 6. A spring-latch 9, suitably mounted upon a down-turned extension 3 of the yoke, engages and holds depressed the switch-spring 4, and upon the return of the armature 7 the back-spring 5 opens away from spring 4. The magnet of relay S is polarized, 'being'provided with the usual permanent magnet 10. In order to restore the spring group to normal, current is sentthrough the magnet in a direction to lift the end of the armature carrying the. insulating button 8, which latter in risingengages an inclined cam portion 9 of the latch-spring 9, and thus trips the latter off.

The ringer relay T is organized in general like the relay S. Its two spools 11 are alike each having two similar windings so wound that when current .is passed through said windings in series the two magnet spools oppose each other and approximately neutralize the inductive effect, as will more clearly appear in'the description of the circuit connections. Upon the yoke 3 of the instrument is mounted a group. of four springs,-a switch-spring 13, a groundingspring 14, a topspring 15 and an intermediate short circuiting spring 16. The ground ing-spring is provided at its movable end with a lateral arm or extension 14, which is bent upwardly around and in position to overlie the end of the switch-spring; said overlying portion carrying a platinum contact point which engages the switch-spring. Between the under side of the switch-spring and the grounding-spring is interposed an insulation 17, desirably mounted on the grounding-spring. The armature 18 of the instrument carries an arm and insulated button 19, which latter in its downward movement engages the portion 14 of the grounding-spring and depresses the latter into contact with switch-spring 13, and thereafter, if the movement is continued, forces the switch-spring into latching engagement with the spring-latch 20, constructed and mounted in a manner similar to the spring 9'Tof the selecting relay described. Both springs 13 and 14 are tensioned to rise when released from the latch, and spring 13 car.- ries a contact 21,-which, when the spring is permitted to rise, closes with top-spring 15 with sufficient tension to lift the latter out of engagement with the short circuiting spring 16. The ringer relay is a polarized instrument. and the latchjis tripped off by-a reversal of current therethrough. substantially as described in connection with the selector relay. When the latch is disengaged.

from the switch-spring, springs 13, 14 and 15are in electrical contact with each other, and the normally closed connection between 1.6 and 16 is open. a G designates a relay. which is 'herein termed'a grounder; the function of this instrument being to automatically establish a ground connection at the end of the partyline which results in restoring the line to normal. This grounder is constructed almost precisely like the selector relay S, except that its switch-spring 22 is normally held down'by a latch-spring 25 in contact with front-spring 23. Upon being released from the latch it rises into contact with the grounding top spring 24. The two spools 26 of this instrument are wound precisely alike and connected in series.

Referring, now, to the diagrammatic drawings, A designates a relay, herein termed the pick-up relay, B a pulsating generator, C a grounding relay, D a line drop,'E a supervisory signal, F the talking battery, and H the operating battery; all of these parts being shown diagrammatically in the conventional way.

The three keys, respectively designated run, ring and pass, are keys used in performing operations aptly described as running, ringing and passing, as will hereinafter appear.

I designates a key employed when it is desired to put two or more parties on the same line in talking connection, and J desi'gnates the operators listening key; the operators set being omitted.

Describing the operations and concerned mechanism, somewhat in the order in which such operations are likely to occur in practice, the subscriber desiring a connection at any station, lifts his receiver from the switch-hook 27, and in so doing establishes a momentary or flash ground from his station to central through the grounded spring 28 which is'arranged to follow the switch-hook in its upward movement until shortly after'the latter has encountered the top-spring 29, but opens before the switchhook reaches its limit of movement. This circuit may be traced from contact 29 to the left line L, through one winding of each intervening magnet spool 1, to the jackspring 30 at central, thence through normally closed contact 31, thence to and through drop D, thence over 32 to battery F, and from opposite side of the latter over 33 to ground. This throws the shutter of the drop. Thereupon the operator inserts the cord plug, the tip 34 thereof engaging spring 30 of the jack and opening the drop circuit, and the sleeve contact 35 engaging the sleeve ring 36. The operator now closes the running key, and in so doing sends pulsating current from the generator -to line over a circuit traced as follows; from positive side of generator over 37 to springs 38, 39, of relay A, thence over 40 to back-spring 41 and key-spring 42, thence over the right side of the cord circuit to right mainline, through included winding of spool 1 of first relay S to switch-spring 4, to topthe left side of the cord wlndings of 'spool 2 of the selector relay, thence over 44 through the windings of both spools 11 of the ringer relay and over 45 to the left main line. The left main line ineludes one winding of spool 1 of the selectorrelay, and at central the circuit is over circuit to running key spring 42', to coiiperating outer spring 41, over conductor 46 to switch-spring 47 of relay A, thence to front-spring 48 and by conductor 41-9 back to negative side of the generator, thus completing the circuit. The first pulsation which. goes to line from the generator, energizes spool 2 of the selector relay, draws down the armature and latches switch-spring 4, and so' opens the bridging connection as to that station and extends the line or link circuit to the next station. In precisely the same manner any number of intervening stations may be passed, a station being passed for each pulsation from the generator. As soon, however, as the link circuit is extended to the station at which the subscriber has called in, a condition is there found which results in automatically arresting the further extension of the loop. It will be noted that switch-hook 27 is connected to the switch-spring, so that when the receiveris removed, and the switch-hook rises, it partially establishes a grounding connection to the left line, which grounding connection is completed whenever thearmature 18 of the ringer relay depresses the grounding sprin sufficiently to close contact with the switch-spring. The adjustment between these contacts is somewhat close, andinasmuch as the armature has little mechanical work to perform, except to bring these sprlngs together during lts m1- tial movement, it follows that the left line is grounded during an early partof the im pulse sent to line. The establishment of the ground at the set stat-ion energizes a circuit which operates relay A, and the latter operates to remove the generator connections from lineand close the main battery H to line in such manner as to reverse the me Tracing this grounded pick-up or arresting circuit, as

it may be termed, and starting at the substation, the circuit is from ground at 50 to grounding-sprlng 14, to switch-spring 13, to switch-hook thence to central, there over the tip side of the cord circuit to spring 42 of the running-key,.and thence to the negative side of the generator, as before described. From the opposite side of the generator the circuit is over 37 to a branch conductor 51, to relay spring 52, relay spring thence over conductor 54 to and through the windings ofthe pick-up relay, thence over 55 to an insulated outer spring 56 mounted outside of and moving with the running key spring spring 5, thence over 43 to and through ,of battery H over 27, to left main line over 29,

42. From spring 56 the circuit is to backcontact 57, thence over 58 to the negative side of the talking battery and to groundover 33 at the opposite side thereof. This energizes relay A, and the armature of the latter in closing changes the positions of its three switch-springs 39, 47 and 53; these being connected to move in unison. During the initial movement of this relay, a

grounding-spring ,59 of relay A brought. IDtO contact with sw1tch-spr1ng 03 thereof.

may be traced as follows: from positive side 62 to spring (31, thence to spring 47, thence over 46 and +11 to spring 42' of running key, out over left side of line to selected station, there over bridg ing connections 45, 441, 43, 5 and 1 to right main line and back to central. From spring 42 of the running key the circuit is to spring 41, thence over 40, to switchspring 39, to top-spring 60, thence over 63 to and through the riglithand spool of relay magnet C, from the latter to normally closed contact 64 of the relay, thence through the armature 65 and over 66 to the negative side of the main battery. This completes the metallic circuit, which it will be observed. is of opposite polarity from the pulsations theretofore sent to line by the generator. It will also be noted that the current-flow of this metallic circuit through the spool of relay C is such as to maintain its armature (i5 closed. At the sub-station the di rection of current flow through the ringer relay is such as to lift the actuating end of the armature and trip oil the latch, thus opening a short circuit over the conductors 67, 67, which includes the receiver, and establishing the talking circuit, which may be traced from the left main line over conductor 29, switch-hook 27, switchspring 13, contact 21., top spring 15, conductor 67, re ceiver G8, conductor 6 9, condenser 70, conductor 71, which latter includes the trans" mittcr 72, and to the left main line. The, current flow which energizes the transmitter is from left main line, over 29 to and through switch-hook, to springs 13, 15, over 79 to 78 and over the latter through the transmitter to right main line. The clap per stem of theringer relay is so connected with the armature that the movement of the latter last described positively oscillates the v clapper and rings the bella single stroke;

battery H to line. The circuit so established posite end of the cord. This end of the.

cord is not shown in the diagram, and may, of course, be either a reproduction of the half shown andemployed with the system now being described or may be any other suitable cord circuit adapted to the character of line upon which the wanted subscriber is located. Assuming, however, that the-subscriber who called in, desires a conmotion with another subscriber upon the same party-line, the operation of completing this connection would vary. depending upon whether or not the subscriber wanted is between the calling subscriber and central or toward the opposite end of the line. In the latter event, the exchange operator upon receiving the order would first direct the subscriber to hang up hisreceiver momentarily. and then proceedas follows: She would first depress key I, thus putting the positive side of the main battery to ground, and thereafter, while still holding the key I closed, would operate the pass-key, the result of these two operations being to extend the circuit from the calling subscribers station to the next succeeding station. without destroying the calling subscribers talking connections. The circuit thus established by the operator would be from ground 73 to key I, thence over 74 to and through the main battery, thence over 75 to the tip side of spring 76 of the pass-key now'in contact with the outer spring 77, and so out over the left main line to the subscribers station who has called. There the circuit would be over 45 to and through one winding of the ringer relay. thence over 44 to and through spool 2 of the'selector relay, thence over 43 to and through contact springs 4 and 5, thence over 71, through transmitter 72 and over a conductor 78 which includes the second winding of the ringer relay. thence over 79 to springs 15 and 13, which latter is connected to ground at 28 through the switch-hook. It will be noted that the circuit so traced passes through both sets of windings of the ringer relay and in such directionthat one winding approximately neutralizes the inductive effect of the other, and this relay accordingly does not operate. The selector relay, however, is energized properly to draw down its armature. latch its switch spring and so extend the link circuit to the next station. Having thus passed the calling subscribers stationthe passing of any given number of additional stations to extend the line to the desired station is ac-.

complished by simply throwing counted out impulses onto the line by repeatedly operating the pass-key, but without holding the auxiliary key I closed. The circuit for these counted out impulses is a full metallic circuit which includes the main battery the same as the circuit last described; the difference in the circuit at the exchange being simply that a top contact 80 carried by the auxiliary key I closes the positive side of the main battery direct to the sleeve side of the cord through the pass-key spring 76 and that the ground at 73 is open. At the subscribers station this circuit is from right main line through springs 4 and 5 of the selector relay, thence over 43, spool 2, conductor 44, magnet winding of the ringer relay and conductor 45 to the left main line. Having thus arrived at the desired station, the operator presses the ringing key which places the negative side of the generator to line through conductor 81, contact82 and key spring 83, and the positive side to line through conductor 84, contact 85 and key spring 83. The first movement of the ringer relay at the station thus selected under this ringing current establishes talking connections, in a manner hereinbefore fully described, and the continued ringing of the bell calls the subscriber to the telephone. In case a subscriber were wanted between the calling subscriber and central, the previously described operations of selecting would be modified only to the extent that the exchange operator after taking the order, would clear or restore the line to normal (as hereinafter described), then first select the nearer subscriber by counting out and passing successive stations until the desired one was arrived at, then having rung this subscribers bell and called him to the telephone, pass on and select the station of the subscriber who originated the call, precisely as before described.

, The system is so organized that whenever the operator has passed all of the stations on the line, either by means of the running key or by'means of the passing key, upo f i f ing at, andpassing an impulse through, the grounder in the passing direction, a ground: ed circuit from upwardly the engaging end of its armature,

thus unlatching and releasing the switchspring 22, which is tensioned to rise and engage the grounding spring 24. The estabcentral to and through the grounder is established which restores.

lishment of this ground which, it will be seen, is upon the left main line (the right line being opened by the' same switching movement) operates the relay-A in precisely the same manner as in set station. A shuntcircuit is also established through the left-hand spool 86 of the relay C which draws down the corresponding end of its armature (i5 and places the opposite end thereof in engagement with a grounding contact 87. The shunt circuit is from top spring 61 of the relay A to a second top spring (31, thence over 88 to and through the relay and over conductor 32 to and through the talking battery, and to ground over 33. As soon as the ground at relay C is closed a circuit. is established from there through the mainbattery, said circuit being from the armature of the relay 65, over (36, through the main battery H, thence over (32 to springs 61' and 4:7, thence over 46 to the sleeve side of the running key, and so out over theilet't main line and to ground at the end of the line. This circuit includes one winding only of each of the several spools l of the several selecting relays S, as well also as both spools of the grounder magnet. The polarity of this circuitis such as torestore the selectors S and grounder Gr to normal. Should it happen that any one of the sub-stations has been passed without restoring the ringer relay, and thus destroying the talking connections, as would, of course, be the case after two or more parties had been placed in talking connection on the same line, the operator will accomplish the restoration of this non-locked out subscribers station by simply running over the line a second time with the passing key.

The circuit connections and arrangement of the supervisory signal E are quite similar to those used in connection with other common battery systems.

Sf) designates a diiterentially wound relay, the windings of which are included in two branches 90 and 91 which lead from the inner springs of the running key to the respective sides of the talking battery. Armature 92 of the differential relay is connected by conductortl -lwith conductor 58 and is adapted to engage when closed a front contact 94: from which the condi"|cto1,- 95 leads to and through the signal lamp and to ground.

So long as there is no ground on the external line, differential 1 day 85) remains open. As soon as the subscriber hangs up his receiver after having been given talking comu-clions, the ground thus established at his station 'closes a grounded circuit over lhe rightthe circuit established from the talking hattery through the lamp connections hercin before described.

lVhile I haveherein shown and described a practical and preferred embodiment.o1 the picking up a I invention, yetit to be understood that the inventionis in no wise limited to this specific embodiment.

I claim as my invention:

1. In a party-line lock-out telephone sys tem, a plurality of sub-stations, a pair of line wires extending through the several sub-stations, bridging connections at each sub-station, a selector relay controlling said bridging connections at each sub-station, a transmitter circuit extending across the main lines at each substation and including both the tansmitter and switch-hook of the telephone set, a lock-out relay controlling said transmitter circuit, said lockout relay having opposed windings, and suitable circuit connections whereby current may be sent concurrently through the selector relay and through either one or both windings of the lock-out relay to effect concurrent operation of both relays or operation of one without operating the other at will. 2. In a party-line lock-out telephone system, a plurality of sub-stations, a pair of.

line wires extending through the several sub-stations, bridging connections at each sul'J-station, a selector relay controlling said bridging connections at each sub-station, a

direct current transmitter circuit extending across the main lines at each substation in shunt relation to the before-mentioned bridging connections and including both the transmitter and switch-hook of the telephone set, a lockout relay controlling said transmitter circuit, said lock-out relay having opposed windings, a source of currentsupply and suitable circuit connections for at will sending current through the selector rclay and one winding only of the lock-out relay, or through the selector relay and through both windings ot' the locleoutrelay.

thin an electrical selecting system, the combination with a pair of main line wires and a source of both grounded and metallic current supply, of two magnets connected in scrics'v across the main lines for operation by metallic circuit, one of said magnets be ing provided, with two windings arranged to oppose each other when current is sentthrough both in series, and means for at will establishing a grounding connection whereby current is sent over one main line and serially througlr both windings of the one magnet and the winding of the other magnot. I

4. in an electrical selecting system, the combinatnm with a pair of main line wires and a source of both grounded and metallic current supply, of two independently oper-- able magnets normally connected in series across the main lilies for operation by me tallic circuit, one of said magnets being provided with two windings arranged to oppose each other when current is sent serially through both, means for sending grounded current over one of said main lines, a grounding branch extending from a on the metallic circuit serially beyon the windings of both magnets, considered wit-h reference to the line over-which said grounded current is sent, back through the opposing winding of the duplex wound magnet and to ground, and contact mechanism operable at will for controlling said grounding branch.

5. In a lock-out telephone system, the combination with a pair of main line wires extending from a central exchange through a plurality of sub-stations, a battery and means for alternatively grounding one side of the battery and connecting the other to one of said main lines, or connecting both poles of the battery to the respective main lines, two independently operable magnets, normally connected in series across the main lines at each sub-station, one of said magnets being a relay magnet and the other being provided with two windings wound to oppose each other when energized by current sent serially through both, a grounding branch extending from a point on the metallic circuit serially beyond the windings of both magnets, considered with reference to the line over which grounded current is sent, back through the opposing winding of the duplex wound magnet and to ground, contact mechanism operable by said duplex wound relay for opening and closing said grounding branch, switch-hook contacts interposed in said grounding branch, and contact mechanism operable by said relay magnct.

(i. In a lock-outtelephone system, the combination of a p'air of main line wires extending from the central exchange through a plurality of sub-stations, one of said lines being sectionalized at each sub-station, a normally closed bridging connection extending from the continuous main line at each sub-station through a lock-out relay and a selector relay in series and to the end of the section there terminating, normally disabled talking circuit connections controlled by said lock-out relay, normally open direct current transmitter circuit connections also controlled by said lock-out relay, contact mechanism controlled by the selector relay for connecting the end of the sectional line there terminating to the initial endof the succccdiug section, and means for transn'iitti ng a call signal to central from each sub station. I

7. In a lock-out telephone system, the combination of a pair of main metallic line wires extending from the central exchangethrough-a plurality of substations, one. of

'said lines beingscctionalized as regards direct current at each sub-station, a normally.

sub-station from the continuous main line oint through a lock-out relay and a selector relay in series and to the end;of the metallic section on the opposite line there terminating, normally open direct current transmitter circuit connections controlled by said lock-out relay, said latter circuit connections including relatively high resistance, contact mechanism controlled -by the selector relay for connecting the end of the sectional line there terminating to the. initial end of the succeeding section, means for establishing an cuit, means at each sub-station for cone necting the continuous line to ground and so operating said diflerentialrelay, anda sig-' nal controlled by said relay.

9. In a party-line telephone system, the combination with an exchange and a plurality of sub-stations, of a metallic link circuit normally completed from the exchange through the first sub-station, electromagnetic station-selecting means at each sub-station for successively extending the link circuit to the next succeeding station, a groundin relayconnected in a normally closed bridge across the main lines beyond the last station, rounding contacts actuated by said groum ing relay and closed when the latter is energized, a source of grounded current connected with the main line circuit and restoring mechanism at each sub-station, whereby upon the extending of said metallic link circuit. beyond the last sub-station said grounding relay is energized, a grounded circuit established and restoration of the selecting mechanisms at the several sub-stations automatically effected.

10. In a common battery lock-out partyline system, a pair of line wires comprising a normally continuous main line and a sectional line, the sections whereof correspond to the reaches between stations, a brid ing connection at each sub-station extending from the terminal portion of the section there terminating to the opposite normally continuous line, a selector relay at each substation controlling such bridging connection and adapted to disconnect the latter and connect the contiguous ends ot sections of the sectional line, whereby a link circuit is successively extended to reach successive substations, means for establishing a transmitter energizlock-out mechanism comprising an intact bridgingconnection at its station. Y

11. In a common battery lock-out partyline system, a pair of line wires comprising a normally contlnuous main line and a sectional line, the sections whereof correspond to the reaches between stations, a bridging connection at each sub station extending from the terminal portion of the section there terminating to the opposite normally continuous line, a selector relay at each substation controlling such bridg ng connection and adapted to disconnect the latter and v sub-stations, lock-out mechanism comprising means for establishing a transmitter-energizing bridging connection at each substation,- switch-hook contacts governing the continuity of the latter circuit, and means for at will establishing a ground-return circuit through the selector relay at each substation, whereby the latter may. be operated to extend the link circuit independently of the existence or non-existence of an intact bridging connection at its station.

EMILIE' Rosa, ALBERT H. GRAVES. 

